CHOLERA

Cholera is an acute intestinal diarrheal disease caused by a bacterium
-- Vibrio cholerae, which is found in water contaminated by sewage.
Cholera occurs both sporadically and in large, abrupt epidemics.

Risk

An epidemic of cholera started in South America in 1991, and has
swept through Central and South America since then. Cholera cases
were first recognized in Peru in the last week of January 1991.
The majority of cases have been reported from Peru, Ecuador, Colombia,
Guatemala, and Mexico. Cholera has been reported in coastal cities
and inland areas of most of these countries. Cholera has also
been reported in Cuzco in Peru and in the Galapagos Islands of
Ecuador. Other countries to report cases include Argentina, Belize,
Bolivia, Brazil, Chile, Costa Rica, El Salvador, French Guiana,
Guyana, Honduras, Nicaragua, Panama, Suriname, and Venezuela.
Bolivia has reported cases as well. Cholera has been reported
from five states in Brazil. Several municipalities near the mouth
of the Amazon River have been affected. Cholera has been reported
in a small number of US residents traveling to Peru and Ecuador.

The risk of infection to the US traveler is very low, especially
those that are following the usual tourist itineraries and staying
in standard accommodations. Cholera germs account for only a small
percentage of all cases of travelers' diarrhea. Very few Western
travelers ever get seriously ill from cholera. In fact, the disease
is reported in only 1 in 500,000 returning travelers. Most illness
occurs in native people who are malnourished and who ingest large
amounts of bacteria from heavily contaminated water. Travelers
should consider the vaccine if they have any problems with their
stomach, such as anti-acid therapy, ulcers, or if they will be
living in less than sanitary conditions in areas of high cholera
activity.

Predicting how long the epidemic in Latin America will last is
difficult. The cholera epidemic in Africa has lasted more than
20 years. In areas with inadequate sanitation, a cholera epidemic
cannot be stopped immediately, and there are no signs that the
epidemic in the Americas will end soon.
Latin American countries that have not yet reported cases are
still at risk for cholera in the coming months and years. Major
improvements in sewage and water treatment systems are needed
in many of these countries to prevent future epidemic cholera.

Signs and Symptoms

The clinical picture of cholera varies widely. The illness in
healthy tourists is usually very mild because they rarely ingest
the heavily contaminated water necessary to trigger the disease.
Severe cases usually strike only the indigenous population. 1
in 20 infected persons gets severe disease. The cholera germs
grow in the small intestine and produce an intestinal toxin that
can cause a massive outpouring of water and salt into the gut.
The toxin does not cause physical damage to the intestinal wall.

There is an abrupt onset of voluminous watery diarrhea, dehydration,
vomiting, and muscle cramps. The onset of the diarrhea is painless
and explosive, and several liters of fluid may be lost every hour.
The rapid loss of salt and water in the stools can cause severe,
life-threatening dehydration. The frequent, watery stools soon
lose all fecal appearance and odor ("rice water stools").
The diarrhea is not bloody and there is no fever. Vomiting generally
occurs but is not associated with nausea. Without treatment, death
can occur within hours. Death from dehydration can occur in up
to 50% of untreated cases.

Diagnosis

Cholera must be distinguished from other causes of travelers'
diarrhea caused by E. coli, Shigella, Salmonella, viruses, and
parasites. The lack of blood, mucus, or pus in the stools of cholera
victims is a distinguishing feature.

Treatment

Managing the effects of dehydration is the mainstay of treatment.
If you can drink sufficient fluids, you can prevent serious dehydration.
Oral rehydration solutions are essential, and their prompt use
has saved many lives. (The World Health Organization rehydration
formula is prepared by adding one packet to one liter of safe
drinking water. Individuals should drink 6 to 8 ounces, or more,
after every loose stool.) If the diarrhea is very profuse and
exceeds what individuals can drink, or if they are vomiting and
can't drink, hospitalization and intravenous therapy will be necessary.

If there is an appreciable delay in getting to a hospital, then
tetracycline should be taken. The adult dose is 250 mg four times
daily. It is not recommended for children aged eight years or
under, nor for pregnant women, because tetracycline stains the
developing teeth of fetuses and children. An alternative drug
is Ampicillin. While antibiotics might kill the bacteria, it is
the toxin produced by the bacteria which causes the massive fluid
loss. Fluid replacement is by far the most important aspect of
treatment. In the hospital, antibiotics such as Furoxone, tetracycline,
Cipro, or Bactrim will shorten the duration of illness and are
important adjuncts to hydration therapy.

Prevention

Travelers to cholera infected areas should follow the standard
food and water precautions of eating only thoroughly cooked food,
peeling their own fruit, and drinking either boiled water, bottled
carbonated water, or bottled carbonated soft drinks.

Following these simple rules, will help you avoid most food and
water borne diseases:

*Drink only water that you have boiled or treated with chlorine
or iodine.
Other safe beverages include tea and coffee made with boiled water
and
carbonated, bottled beverages with no ice.

*Eat only foods that have been thoroughly cooked and are still
hot, or fruit
that you have peeled yourself.

*Avoid undercooked or raw fish or shellfish, including ceviche.

*Make sure all vegetables are cooked.

*Avoid all salads.

*Avoid foods and beverages from street vendors.

*A simple rule of thumb -- Boil it, cook it, peel it, or forget
it.

The available vaccine is only 50% effective in reducing the illness,
and is not recommended routinely for travelers. The primary series
is normally two injections with booster doses given every 6 months
for persons who remain at high risk. Cholera vaccine is not recommended
for infants under 6 months old, or for pregnant women.

If you are exposed, the vast majority of cholera germs that you
ingest will be destroyed in your stomach by gastric acid. The
cholera vaccine offers little protection and is no longer officially
recommended by the World Health Organization. The antibodies produced
by the vaccine have little effect upon the germs in your intestine.
Marginal benefit from vaccination may occur in those travelers
with (1) low-protective gastric acid levels (e.g., people taking
anti-ulcer drugs) and (2) those on long-term assignment in high-risk
areas where there is poor sanitation and the possibility of exposure
to heavily contaminated water. Otherwise, the only indication
for the vaccine is to satisfy the entry requirements of certain
countries.